84/85 RM125 tank to RM250 Conversion?

MXVet261
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Edited Date/Time 5/10/2014 1:53pm
Another thread on here reminded me about this.

I've been meaning to check into this for my '84 RM250 below, and I have an '84 RM125 tank available. Can anyone tell me what needs to be done to put the smaller 125 tank on the 250?

I'm sure I could figure it out if I really start digging into it, but if anyone has already done it that always helps.

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MaxPower
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3/22/2014 6:02pm
Have you heard of it being done before between those bikes? Most vintage 250 and open bikes would look so much better with a smaller 125 tank.
Other than swapping tank and shrouds I'm thinking the only thing that would keep you from making the switch would be if the pipe came up on the opposite side and hit the gas valve.
The 84 was a cool looking bike. It looked just like the Works bikes Suzuki was racing at that time
sandman768
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3/23/2014 5:35am
I posted same question on "atmoto" and have not 1 reply! I know it was done back in 84&85, Barnetts bikes had 125 tank on them for SX. I have been planning on picking up 125 tank to do it, I think minimum we may have to reroute the small radiator hose that crosses over the top of frame in front of the tank, on the 125 this hose is lower & goes through a frame hole. other than that, I'm not sure. will have better tank to pipe clearance than the 250 tank, as the 125 tank, does not have that large "belly' on the bottom rt side. the stock 250 tank is massive, like a hare scramble tank! A while ago, some one had a Barnett practice bike for sale in PA. the pho's & notes stated in had a stock 84-88 rm 125 gas tank on it, looks & I'm sure feels much better. Stock tank likely for 45 min motos!
barkhard696
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3/24/2014 6:35am
I looked into this conversion from the other end back in '08. I had an '85 RM125F and wanted to mod the frame to put in an '82 RM250 motor. Even back in '84 people were unhappy with the big tank and IIRC were trying to figure how to put the 250 motor in the 125 frame.

The reason I say this is, changing the 250 tank/seat is not just a bolt-in-swap conversion. You need new radiators, new rad mounting points, hoses, pipe mounting points, etc. etc. At least that's as far as I was able to determine before I dropped the project.

You are correct that Barney's WORKS bikes in '82/'83 ran the much smaller 125-style setup with the 250 motor.

When he was having issues with the '84 works RA250 (the one with infamous airbox and tank in switched locations), he gave up and simply switched to running a stock RM250. From that point on, all the pictures I saw of him at SX were on a stock RM250. IIRC I saw him at the '84 Astrodrome SX and he was already running a stock bike.

It seems to me that if The Bomber (The Man at Suzuki at the time, the first $1 million dollar rider in motocross), had to run a stock '84 RM250 with a big tank, it seems reasonable that you can't just swap out the seat/tank. I believe those are the least of it. I think you need to get a complete '84/'85 RM125 core and then mod the frame to fit the motor. If you could do that, especially if you had a good '82 RM250 motor, you'd have a great bike.

Apologies if this is a negative post. My research when I looked into this could be all wrong, and I'd loved to be proven mistaken.
MXVet261
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3/24/2014 9:52am
That's what I was looking for. I've had some people tell me "yeah just swap out the tank" but when I briefly looked at it I saw no easy way.

The Shop

sandman768
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3/24/2014 11:01am
I was at World vet race at glen Helen this fall. A guy pitted next to us, his name was Ed Tashjian. He had an 84 rm 250 with a 125 tank on it. I looked it over briefly & asked how hard was swap, he said "not that bad". I should have paid closer attention & got his phone #. I was racing multiple classes & did not have time for a vintage bench session. My bad! I have tried to find this person on a few other boards with no luck. He can tell us exactly what needs to be done. If the swap entails all that
"Barkhard" says, then I will pass. I don't want to chop up my bike for the mod. No negativity taken Barkhard, we are just looking for a better way and the more input the better!
rodb
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3/24/2014 3:47pm
You can find Ed Tashjian on full floater,Some of the items you will need rm 125 gas tank,rm 125 radiators&shrouds.
Also will have to remove radatior bracket on the back bone of frame.
barkhard696
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3/24/2014 5:36pm
Yeah, I've dealt with Ed. First class guy. I forgot about his conversion. The FullFloater.com site is run by a buddy of mine, Marc Shade. Ask him to hook you up with Ed, both are super cool dudes. Ed has some of the best RMs in the United States, all kinds of works stuff. I'd love to see the conversion!
sandman768
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3/25/2014 1:33am
Yes, Ed was super cool, we talked for 1/2 hr. He has some awesome works RM's. If what "Rodb" says is accurate, I likely will not do the conversion, I should have looked into during the build of that bike. The bike is very clean & original, I will leave it that way. For the amount of times I will actually ride the bike, it would not be worth it. I promised myself I would not make garage queens out of these bikes, but that is what always seems to happen. I ride them a few times, dial them in best I can, then move on to the next 1.
Suzuki Ed
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5/7/2014 7:27pm
MXVet261 wrote:
Another thread on here reminded me about this. I've been meaning to check into this for my '84 RM250 below, and I have an '84 RM125...
Another thread on here reminded me about this.

I've been meaning to check into this for my '84 RM250 below, and I have an '84 RM125 tank available. Can anyone tell me what needs to be done to put the smaller 125 tank on the 250?

I'm sure I could figure it out if I really start digging into it, but if anyone has already done it that always helps.

Hello Pit Racer , the swap is a bit involved . It does require that you bore a hole through the steering neck for the radiator crossover tube , also removing the upper rear radiator mount on the backbone , also the lower radiator mounts on the frame have to be lowered about an inch . Thats pretty much the mods to the frame . Then I use 84 / 85 125 radiators and shrouds remove the upper rear tab from the radiators , from there fab some mounts for the radiators to connect them together at the bottom . So now that the radiators set lower you have to build a pipe to clear the right side radiator on the bottom . In thinking about it after the fact i've wondered if it would've been easier to just install a 250 motor in a 125 frame .
Suzuki Ed
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5/7/2014 7:30pm
MXVet261 wrote:
Another thread on here reminded me about this. I've been meaning to check into this for my '84 RM250 below, and I have an '84 RM125...
Another thread on here reminded me about this.

I've been meaning to check into this for my '84 RM250 below, and I have an '84 RM125 tank available. Can anyone tell me what needs to be done to put the smaller 125 tank on the 250?

I'm sure I could figure it out if I really start digging into it, but if anyone has already done it that always helps.

Suzuki Ed wrote:
Hello Pit Racer , the swap is a bit involved . It does require that you bore a hole through the steering neck for the radiator...
Hello Pit Racer , the swap is a bit involved . It does require that you bore a hole through the steering neck for the radiator crossover tube , also removing the upper rear radiator mount on the backbone , also the lower radiator mounts on the frame have to be lowered about an inch . Thats pretty much the mods to the frame . Then I use 84 / 85 125 radiators and shrouds remove the upper rear tab from the radiators , from there fab some mounts for the radiators to connect them together at the bottom . So now that the radiators set lower you have to build a pipe to clear the right side radiator on the bottom . In thinking about it after the fact i've wondered if it would've been easier to just install a 250 motor in a 125 frame .


Here's a photo of how it turned out , tried to build it as an RH83 Works Replica
BigAl
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5/7/2014 8:00pm
I think I have a nice set of radiators and a decent set of shrouds
sandman768
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5/8/2014 4:36am
Pit racer: did u get that 84 from a guy in upstate NY, just outside Syracuse? Thanks for the info Ed! your bike is great! I thought this would be an easy swap, I have a super clean original 84 250. don't want to start cutting it up. I spoke with you at last years world vet race, I was renting a bike from Dave Fontes @ mx vacations. My 84 is all done, have not fired it up yet since complete restoration, looks so good, almost don't want to ride it, but, I have to test my work!
barkhard696
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5/8/2014 5:25am Edited Date/Time 5/8/2014 5:59am
Hey Ed, welcome to the forum! Your bikes are always amazing, and its exciting to see what new creations you've been working on. Thanks for the info, see you on FullFloater.com!

PS. Your '83 RA250 replica, is the BOMB! But so was your '81 RA250, your works bikes, etc :-) I'm still looking for an '84 RM500 swingarm for my '82 like you used on your '81 RA replica. You sir-- are a stone Suzuki master! -- James
Suzuki Ed
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5/8/2014 6:56am
sandman768 wrote:
Pit racer: did u get that 84 from a guy in upstate NY, just outside Syracuse? Thanks for the info Ed! your bike is great! I...
Pit racer: did u get that 84 from a guy in upstate NY, just outside Syracuse? Thanks for the info Ed! your bike is great! I thought this would be an easy swap, I have a super clean original 84 250. don't want to start cutting it up. I spoke with you at last years world vet race, I was renting a bike from Dave Fontes @ mx vacations. My 84 is all done, have not fired it up yet since complete restoration, looks so good, almost don't want to ride it, but, I have to test my work!
Your 84 came out very nice , i understand you not wanting to modify it . I have another 84 that is in pretty good condition and I felt the same way about tearing into the frame so I found another frame . I thought about it for awhile , thinking of taking the motor out of my original 84 and swapping it after the frame was modified but ditched that idea . I wound up finding a good core bike with a standard bore cylinder and used that that bike , still have a really good frame . I have so many spare parts I was able to put a complete bike together fairly easy . If you go the the Floater website photos you'll see some photos I posted during the build , they are a ways back so you'll have to hunt for them .
Suzuki Ed
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5/8/2014 7:22am
Hey Ed, welcome to the forum! Your bikes are always amazing, and its exciting to see what new creations you've been working on. Thanks for the...
Hey Ed, welcome to the forum! Your bikes are always amazing, and its exciting to see what new creations you've been working on. Thanks for the info, see you on FullFloater.com!

PS. Your '83 RA250 replica, is the BOMB! But so was your '81 RA250, your works bikes, etc :-) I'm still looking for an '84 RM500 swingarm for my '82 like you used on your '81 RA replica. You sir-- are a stone Suzuki master! -- James
Thanks James I just sold a complete 84RM500 swing arm 3 weeks ago with linkage , struts , cushion lever , chain guide and chain buffer . I had originally put it on my 81 but just the swing arm only using the the standard 81 cushion lever and it just didn't work right . I didn't have the 84 cushion lever so I went back to the 81 swing arm . I ended up finding everything I needed to convert my 83 RM500 to the 84 set up but realized once I was swapping the parts over that the pivot shaft diameter for the cushion lever is larger diameter . I would've had to drill out my frame to except it and didn't want to take that chance . So as it turns out I sold it all pretty quick once I listed it .
barkhard696
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5/8/2014 11:53am
>So as it turns out I sold it all pretty quick once I listed it .

Arrgh! I've had a watch on eBay for months for that darn swingarm. Well, it certainly sounds like it wouldn't have worked anyway.

What are you thoughts on getting a 250 motor into the '84-'85 125 frame? I'd love to put the '82 250 motor into that combo, this is what Marc and I were talking about with that low-hour '85 125 and the '82 250 I ended up swapping him. He later sold both bikes on FullFloater, I believe, so you might remember them.

I still think that next to the '03 SoBe bike, the '83 RA250 is the trickest bike Suzuki ever made... and would love to build a replica one day. And did you make the pipe for your swap yourself? (Full-on thred highjack in progress!)
MXVet261
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5/9/2014 10:35am
sandman768 wrote:
Pit racer: did u get that 84 from a guy in upstate NY, just outside Syracuse? Thanks for the info Ed! your bike is great! I...
Pit racer: did u get that 84 from a guy in upstate NY, just outside Syracuse? Thanks for the info Ed! your bike is great! I thought this would be an easy swap, I have a super clean original 84 250. don't want to start cutting it up. I spoke with you at last years world vet race, I was renting a bike from Dave Fontes @ mx vacations. My 84 is all done, have not fired it up yet since complete restoration, looks so good, almost don't want to ride it, but, I have to test my work!
No I built that bike out of two bikes worth of parts, one from Ohio and one from Kentucky.

Thanks for all the info. That bike looks awesome! I think though I will just leave mine as is now that I have the real story and not just the "you should swap, it's easy!" comments from others in the past. Tongue
MaxPower
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5/9/2014 7:10pm
PitRacer and Suzuki Ed . Both your bikes make me want a 84 250. I love the look of the 125 tank . I think you should go for it Pot Racer.
Is the rear fender on official factory part or did you modify the stocker in some way?
barkhard696
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5/9/2014 7:17pm Edited Date/Time 5/9/2014 7:20pm
>Is the rear fender on official factory part or did you modify the stocker in some way?

Believe that's the Stilmotor (very close) replica of the factory '80-'3 rear fenders. I've been looking for one for some time myself. Ed has contacts and the builds I've seen of his have used this rear fender.
Suzuki Ed
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5/9/2014 9:39pm
>Is the rear fender on official factory part or did you modify the stocker in some way? Believe that's the Stilmotor (very close) replica of the...
>Is the rear fender on official factory part or did you modify the stocker in some way?

Believe that's the Stilmotor (very close) replica of the factory '80-'3 rear fenders. I've been looking for one for some time myself. Ed has contacts and the builds I've seen of his have used this rear fender.
Yes it is a Stilmotor works replica fender , and yes it is very close to the works unit . I've been fortunate to find them , I have 3 Stilmotor one being NOS in a box . My83 500 I was lucky to find a M Robert' that is a direct bolt on for the 81thru 83 125 & 250 also for the 81 thru 84 465/500 . They fit really good , as for the Stilmotor thats a different story . There wider and a bit shorter so some work is needed to get them to fit . This 84 if you look close has Works 43mm top & bottom triple clamps , I built an adjustable brake torque arm using a solid piece of rectangular aluminum stock with an adjustable rod end at the front and if you look real hard you'll see a Works 40mm Mag flat slide Mikuni carb. Bike has quite a bit of Ti fasteners as well . I do have a set of works radiators and shrouds that I thought of using on this build but chose to use the 84 125 production radiators instead . Would've looked really good , the left side radiator is really long and hangs lower then the right side .
barkhard696
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5/10/2014 1:53pm
Ed, your stuff is incredible. I'm grateful for your advice over the last couple of years; I'd forgotten about the M. Robert fender.

Any chance of you doing you next build here? Also, whenever you sell parts will that only be on FullFloater.com?

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